High sensitivity and ultra compact fiber-optic microtip SPR thermometer coated with Ag/PDMS bilayer film

In this paper, we report an ultra-compact reflective SPR micmtip temperature probe, which can achieve 2-D spatial resolution of several microns. The pencil-shaped all-fiber micmtip proposed by us is a SO2 conecylinder with a length of 40 mu m and a gradient diameter of 2 mu m-10 mu m, which can be used to develop multitype tiny functionalized sensors. Due to the strong evanescent field of the ultra-fine microtip, the surface plasmon resonance (SPR) can be effectively stimulated by depositing nano-silver (Ag) film on its surface. Owing to the high refractive index (RI) sensitivity of SPR effect and the high thermo-optic coefficient (TOC) of polydimethylsiloxane (PDMS), the temperature sensitivity of microtip SPR probe coated with PDMS micron-film can reach to 1.985 nm/degrees C. Teflon 1600 nano-film on the surface of the SPR thermometer can effectively enhance the non-stickiness, moisture-proof and wear resistance. The test results show that the probe is hardly disturbed by humidity. This new sensing platform can be demonstrated by assembling high-performance sensing materials and ultra-compact fiber-optic structures.

Automated summary

The ultra-compact reflective SPR micmtip temperature probe has high sensitivity and temperature coefficient, suitable for developing various functionalized sensors. Adding Teflon 1600 nano-film on the surface can enhance non-stickiness, moisture-proof and wear resistance, while being hardly disturbed by humidity.